A second case of recessive mosaicism in ABCA12 causing a congenital unilateral epidermal nevus

We report a patient with a congenital unilateral epidermal nevus caused by two novel pathogenic ABCA12 variants, one inherited and one postzygotically acquired. This represents a rare example of recessive mosaicism, previously described only once. Our case corroborates and extends current knowledge of this mechanism and highlights its relevance for diagnostics and genetic counselling.